topdown: glob|regex code nitpicks (#7071)

No functional changes, just

- using ast.String(..) instead of ast.StringTerm(..).Value
- using const where package-level strings never change (metrics names)

Signed-off-by: Stephan Renatus <stephan@styra.com>

topdown/glob.go

@@ -11,12 +11,11 @@ import (
 )
 
 const globCacheMaxSize = 100
+const globInterQueryValueCacheHits = "rego_builtin_glob_interquery_value_cache_hits"
 
 var globCacheLock = sync.Mutex{}
 var globCache map[string]glob.Glob
 
-var globInterQueryValueCacheHits = "rego_builtin_glob_interquery_value_cache_hits"
-
 func builtinGlobMatch(bctx BuiltinContext, operands []*ast.Term, iter func(*ast.Term) error) error {
 	pattern, err := builtins.StringOperand(operands[0].Value, 1)
 	if err != nil {
@@ -62,34 +61,29 @@ func builtinGlobMatch(bctx BuiltinContext, operands []*ast.Term, iter func(*ast.
 func globCompileAndMatch(bctx BuiltinContext, id, pattern, match string, delimiters []rune) (bool, error) {
 
 	if bctx.InterQueryBuiltinValueCache != nil {
-		val, ok := bctx.InterQueryBuiltinValueCache.Get(ast.StringTerm(id).Value)
+		val, ok := bctx.InterQueryBuiltinValueCache.Get(ast.String(id))
 		if ok {
 			pat, valid := val.(glob.Glob)
 			if !valid {
 				// The cache key may exist for a different value type (eg. regex).
 				// In this case, we calculate the glob and return the result w/o updating the cache.
-				var res glob.Glob
 				var err error
-				if res, err = glob.Compile(pattern, delimiters...); err != nil {
+				if pat, err = glob.Compile(pattern, delimiters...); err != nil {
 					return false, err
 				}
-				out := res.Match(match)
-				return out, nil
+				return pat.Match(match), nil
 			}
 			bctx.Metrics.Counter(globInterQueryValueCacheHits).Incr()
 			out := pat.Match(match)
 			return out, nil
 		}
 
-		var res glob.Glob
-		var err error
-		if res, err = glob.Compile(pattern, delimiters...); err != nil {
+		res, err := glob.Compile(pattern, delimiters...)
+		if err != nil {
 			return false, err
 		}
-		bctx.InterQueryBuiltinValueCache.Insert(ast.StringTerm(id).Value, res)
-
-		out := res.Match(match)
-		return out, nil
+		bctx.InterQueryBuiltinValueCache.Insert(ast.String(id), res)
+		return res.Match(match), nil
 	}
 
 	globCacheLock.Lock()

topdown/regex.go

@@ -16,12 +16,11 @@ import (
 )
 
 const regexCacheMaxSize = 100
+const regexInterQueryValueCacheHits = "rego_builtin_regex_interquery_value_cache_hits"
 
 var regexpCacheLock = sync.Mutex{}
 var regexpCache map[string]*regexp.Regexp
 
-var regexInterQueryValueCacheHits = "rego_builtin_regex_interquery_value_cache_hits"
-
 func builtinRegexIsValid(_ BuiltinContext, operands []*ast.Term, iter func(*ast.Term) error) error {
 
 	s, err := builtins.StringOperand(operands[0].Value, 1)
@@ -107,17 +106,13 @@ func builtinRegexSplit(bctx BuiltinContext, operands []*ast.Term, iter func(*ast
 
 func getRegexp(bctx BuiltinContext, pat string) (*regexp.Regexp, error) {
 	if bctx.InterQueryBuiltinValueCache != nil {
-		val, ok := bctx.InterQueryBuiltinValueCache.Get(ast.StringTerm(pat).Value)
+		val, ok := bctx.InterQueryBuiltinValueCache.Get(ast.String(pat))
 		if ok {
 			res, valid := val.(*regexp.Regexp)
 			if !valid {
 				// The cache key may exist for a different value type (eg. glob).
 				// In this case, we calculate the regex and return the result w/o updating the cache.
-				re, err := regexp.Compile(pat)
-				if err != nil {
-					return nil, err
-				}
-				return re, nil
+				return regexp.Compile(pat)
 			}
 
 			bctx.Metrics.Counter(regexInterQueryValueCacheHits).Incr()
@@ -128,7 +123,7 @@ func getRegexp(bctx BuiltinContext, pat string) (*regexp.Regexp, error) {
 		if err != nil {
 			return nil, err
 		}
-		bctx.InterQueryBuiltinValueCache.Insert(ast.StringTerm(pat).Value, re)
+		bctx.InterQueryBuiltinValueCache.Insert(ast.String(pat), re)
 		return re, nil
 	}